Warhead



Oct. 14, 1969 F.=E. NULL 3,472,165

WARHEAD Filed March 28, 1963 2 Sheets-Sheet INVENTOR. I74) .5. 11/044Oct. 14, 1969 F. E. NULL 3,472,165

WARHEAD Filed March 28, 1963 2 Sheets-Sheet INVENTOR fit/2 4 0 l UWUnited States Patent 3,472,165 WARHEAD Fay E. Null, Shalimar, Fla.,assignor to the United States of America as represented by the Secretaryof the Air Force Filed Mar. 28, 1963, Ser. No. 268,841 Int. Cl. F42b/00, 3/00 US. Cl. 102-1 17 Claims The invention described herein may bemanufactured and used by or for the United States Government forgovernmental purposes without payment to me of any royalty thereon.

This invention relates generally to warheads and, more particularly, toan imploded cloud warhead.

Conventional warheads utilize an outward explosion in order to causefragments to hit a target after detonation of the explosive. These typesare inherently ineflicient compared with the instant invention since theoutwardly directed explosion causes a decrease in the detonation Wavevelocity as the radius increases, and the average pressure within asphere, including the warhead and target, decreases approximately as thecube of the radius. Thus, the fragment pattern density, and radiationare caused to fall off approximately as the radius squared.

The present invention has an opposite eifect produced on a target whichis located at the center of an imploding warhead. With this situation,the detonation wave velocity increases as the radius decreases, and theaverage pressure increases approximately as 1/r while the density offragments and radiation increase as l/r with the decreasing radius.

The invention comprises a warhead having an outwardly moving cloud orgenerally spherical shell of explosive particles with light, outwardlymoving detonators which maintain a peripheral position around the cloudor shell. The detonators are fused and may be timed to be fired in theiroptimum relative phases which would produce an implosion with a highvelocity shock wave which impacts the target near the center or at theedge of the cloud. In addition, darts or rods with attached parachutestructures may be positioned in a layer inside the shell of explosiveparticles such that the high velocity shock wave and the detonationproducts behind the shock wave pro el the darts or rods to produce ahigh velocity layer of projectiles capable of penetrating a target.

The foregoing arrangement has particular utility in dudding nuclearbombs and satellites, since a cloud of explosive several hundred feet indiameter is possible with the apparatus of this invention.

Accordingly, it is an object of this invention to provide a novel methodand apparatus for dudding nuclear weapons, missiles and satellitevehicles.

It is another object of this invention to produce a novel warhead andmeans for forming it to produce a greater destructive effect upon atarget than has been heretofore achieved.

It is still another object of this invention to produce a novel methodand apparatus for creating an outwardly moving cloud or spherical shellof explosive particles.

It is a further object of this invention to produce a novel warheadstructure comprising a cloud of explosive particles with outwardlymoving detonators maintaining a peripheral position therearound andprojectile means capable of being directed inwardly against a target.

It is a still further object of this invention to provide a novelimploding warhead which has its detonation shock wave enhanced by aconvergent wave front.

These and other advantages, features and objects of the invention willbecome more apparent from the followice ing description taken inconnection with the illustrative embodiments in the accompanyingdrawings, wherein:

FIGURE 1 is a schematic representation of a cloud type warhead forillustrating the theory and technique of this invention;

FIGURE 2 is a graphic representation of the effect of an imploded cloudwarhead upon a target at the edge of the cloud with proper triggering ofthe warhead;

FIGURE 3 is a pictorial view of a dart and parachute structure which maybe utilized with the warhead of this invention;

FIGURE 4 is a cross-sectional view of the emitting end of the means forcreating the cloud of explosive material;

FIGURE 5 is a schematic representation of a unit capable of setting outthe cloud, detonators and projectiles for the warhead; and

FIGURE 6 is a view in elevation of the premixing and feed device for thepreparation of the explosive medium.

Referring to FIGURE 1, there is illustrated a spherical shell 10 ofexplosive particles having limits between phantom lines A and B.Detonators 12, shown arbitrarily at 45 intervals, are peripherallylocated and arranged to be fired simultaneously. The resultant shockwave from the firing of the explosive particles by the detonatorstravels across the gap to impact the target T from all directions,simultaneously. The pressure of this type of implosion is great enoughto collapse any light target structure such as the pressurized cabin ofa satellite. If required, an arrangement of darts 14 may be locatedwithin the explosive shell 10. The dart assemblies 14 haveparachute-like structures such that the passage of the detonation wavefrom the explosive particles and the resultant high velocity of thecombustion products behind shock wave fronts are caused to impact on thefiber parachutes to cause the dart assemblies 14 to converge behind theconverging shock wave until the gaseous products of the implosion areimpacted at the center, thereby stopping parachutes and allowing thedart elements to penetrate the target T.

When a target is not centrally located as shown in FIGURE 1, anefiicient target destructive force may still be realized by utilizingthe implosion principles illustrated in FIGURE 2. This device utilizesthe same structural relationship with the explosive detonators 12 and,if desired, the darts arrangement 14 except that a 30 interval is chosenfor the detonators; however, the symmetry of the arrangement of FIGURE 1is destroyed by the oif-center position of the targe T In an applicationof this type the detonator firing times are arranged such that the timebetween each individual detonator firing and the impact of its initiatedwave on the targe T is proportional to the distance the detonation wavehas to travel from the detonator firing point to the target. Thearrangement of the firing times insures the arrival of the detonationwaves shown and darts 14 from all directions on the target at the sametime. This application may have almost as large a destructive elfectupon the target as that shown in FIGURE 1, especially where the velocityof the target relative to the cloud is very great.

The dart arrangement 14 is shown in FIGURE 3 and the individual dartsare comprised of rods or conventional dart shaped metallic objects 16having a series of shroud lines 18 attached to a collar 20 whichsurrounds the projectile. The projectile may have a shoulder 22 thereonto allow removal of the collar in only one direction. The shroud lines18 are attached to a canopy or parachutelike structure 24 which may beof quartz fiber in order to resist the effects of the combustionproducts. The canopy 24, after the detonation wave has passed over thedarts, is carried along behind the shock wave by the high velocitycombustionproducts until it reaches the target T or T at which time thegases impact and stop the assembly, thereby allowing the projectiles 16to continue through the canopies 24 and release themselves, ifnecessary, from the collar 20.

The explosive shell or cloud is manufactured or created by means of asiren type ejector 26 as shown in FIGURE 4. The device creates tinydroplets of explosive liquid and is actuated by high pressure from apropellant gas. Once a droplet is launched from the ejector it starts toevaporate at a very fast rate. The evaporation, however, first requiresa freezing of the liquid which reduces its temperature. The latent heatof the evaporation is greater than the heat of fusion and the specificheat until the temperature is reduced to about 32 K., at which point thevapor pressure of the drop is balanced by that of the vacuum environmentas would be found near space vehicles. Liquid for making the explosivepellets forming the shell 10 is fed through an inlet pipe 28, and holes30 in this pipe allow the liquid to enter the rotor reservoir indicatedby the numeral 32. The rotor 34 is secured to the inlet pipe 28 whichforms a hollow shaft for rotation of the unit. The stator 36 has in thehemispherical portion 38 a large number of spaced apart holesschematically illustrated at 40. Both the rotor 34 and stator 36 have aground fit therebetween and would conveniently be made of glass. Theholes 40 may be placed in the hemispherical portion 38 by means of aphotographic reduction and etching process since their diameters andrelationships are not critical. Rotation of the rotor 34 causes the flowof the liquid, which forms the explosive particles, around the centralhollow element 42 of the rotor 34 against surface 44 of the rotor whichhas longitudinally oriented slots 46 connected with holes throughsurface 38 to receive fluid from the rotor reservoir 32. Thelongitudinal slots 46 revolve under the stator holes 40 thereby causingan emission of small droplets 48 from the stator 36.

The cloud material, after it is frozen, can be detonated by shocksimilar to shock action on a gas, since molecular impacts have equalvelocity, and all molecules on the solid surface are impacted by theshock layer. Assuming there is no detonation of the pellets formed bythe droplets 48, the relatively large ratio of area to mass allows thepellets to pickup the velocity of the shock flow. This causes completeevaporation of the pellets a very short distance behind the shock wavefront, at which point their combustion would add energy to the shockfront in the same manner as if the pellets were detonated.

Thus, it can be seen that once a detonator produces its wave it will bepropagated inwardly even in a rare explosive medium because the shockwave is enhanced by a convergent form. Although the individual particlesproduce wavelets similar to those in an explosion, the detonation wavefrom the pellets spread spherically; however, the imploded wave frontforms from the combination of the wavelets from a spherical shell ofdetonation points and is greatly increased in strength.

When the droplets 48 are sprayed from the dispenser 26 to form thecloud, either a small propellant charge or a source of pressurized gasis utilized to project a layer of dart assemblies 14 from a series oftube launchers. The arrangement shown in FIGURE schematically disclosesthe assembly which creates the cloud and positions the darts and thedetonators. The device comprises a sphere 50 within which a source ofpressurized gas and propellant is stored and, in addition, contains themechanism operated by the pressurized gas to cause rotation of the rotor34 and its shaft 28. A series, only a few of which are shown, of dartprojectors 52 are clustered around a conventional rifled detonator gun54, the locations of which are in conformance with the final placementof the darts and detonators. The spherical housing 50 is projected orlaunched to the target site, and, when it reaches the appropriatelocation, conventional triggering means, such as a computer operatedradio control, may be utilized to cause the pressurized gas source torelease its pressure to drive a mechanism, for example, a turbine wheel,to cause rotation of the siren type ejectors 26 and at the same timeforce liquid to be pelletized through the shaft 28. This action causesthe creation of the cloud and propellant particles. When the propellantcloud is formed, or while it is formed, the detonator guns 54 and dartprojectors 52 are caused by gas pressure or explosive means to projecttheir respective payloads outwardly such that, at the appropriate time,the detonators are located at the outer periphery A of the formed shell10 of pellets. The dart assemblies 14 will have assumed a positionwithin the warhead 10 adjacent the limit B.

Although the foregoing arrangement has been described relative to radiocontrol which may be operated by a conventional computer, the unititself could provide the signal for exploding the detonators, forexample, by means of light sources at 56 which could be made to actuatedetectors in the detonators to trigger the explosive therein.

The description thus far has utilized droplets of explosive liquid forcreating the cloud; however, it should be understood that the cloud maycomprise dust particles blown by nozzles with compressed air rather thanutilizing the ejector shown in FIGURES 4 and 5. Layers of adsorbed airsurrounding the dust would prevent detonation during its flow throughthe nozzle. Alternatively, an explosive which is made insensitive by acoating of, for example, alcohol, might be utilized such that theejected particles would have their coating evaporated very quickly in avacuum environment. The particles then would become very sensitive toshock and could be readily detonated.

Storage of liquids, which upon mixing become the explosive mixture, mayinvolve some hazards if stored in the mixed state. Therefore, theembodiment of FIGURE 6 provides for the feeding of the oxygen andmethane liquids which form the pellets. This apparatus would be mountedwithin the sphere illustrated in FIGURE 5. The mixing apparatuscomprises a drive piston rod 60 which might be actuated by compressinggas within the sphere at a predetermined time on the recept of a signal.Movement of the drive piston rod 60 forces pistons within the methancylinder 62 and the oxygen cylinder 64 to move to the right asillustrated in the drawings. Both the oxygen and methane are forcedthrough separate tubes 66 and 68 from their respective cylinders into amixing chamber 70 wherein the two fluids are joined. The mixing chamberis attached to direct the premixed fluid by means of conduit 72 to anultrasonic mixing chamber 74. The ultrasonic mixing chamber comprises aconvoluted passageway having wedges 75 therein which are actuated by a30 kc. signal to cause resonance of the wedge, thereby producing acomplete mixing of the two liquids. The output from the ultrasonicchamber 74 is directed back through feed line 75, check valve 82 andconduits 80, 76 and 78 into the cylinders 62 and 64, which originallycontained the methane and oxygen in separated conditions.

The piston rod 60 may be attached to a piston 86 in a cylinder 90, atthe end of which an explosive charge 88 may be fired to cause theaforesaid movement of piston rod 60. Upon a signal to eject theparticles, the drive piston rod 60 is reversed in direction by actuatingin a conventional manner the explosive charge 92 at the opposite end ofthe cylinder from explosive charge 88. Motion of the piston rod 60 andits connected pistons in cylinders 62 and 64 causes the premixed fluidto be directed through conduits 76, 78 and 80, through check valve 82and a diaphragm 84 to the ejectors. The diaphragm 84 is arranged to beruptured only upon movement of the piston rod 60 in its reversedirection. The diaphragm 84 functions to divert the fluid when it isbeing transferred from the ultrasonic mixer 74 to the cylinders 62 and64.

The imploding cloud concept of this invention would permit lbs. ofexplosive pellets and 65 lbs. of darts to be dispersed to form a hollowshell to produce a great concentration of fire power and pressure. It iscontemplated that at the start of the implosion 1.08(10) lbs. per cubicfoot of 1.0(l0) inch diameter pellets of solid oxygen and methane wouldproduce a detonation velocity of 9,200 feet per second. Approximately5,680 darts would acquire this velocity in two feet of depth of theimploding gas, thereby presenting a capability for dudding nuclearweapons. Each dart would be approximately 1.0 inch long with a diameterof 1.66 inches and a weight of 6.18()- lbs. Thus, a large number ofdarts may be fanned out from the individual dart guns 52. The pellets,detonators and the darts are projected at a velocity of 500 feet persecond. Thus, with proper timing, the elements will assume the positionshown in FIGURE 1 or 2. The droplets which are projected at theaforementioned velocity would b aproximately .001 inch in diameter witha linear spacing of the same amount. This may be achieved by the holesin the stator having the same diameter and spacing. It is contemplatedthat approximately 4(10) holes placed in the stator will produce theproper structural arrangement for creation ofthe cloud. Each sirenejector, which ejects the droplets, is arranged to spray 1,830 cubicinches of liquid in .Olsecond at 1,900 lbs. per square inch in order togive the droplets sufiicient kinetic energy. Sixteen (16) lbs. persquare inch pressure i required ,to overcome the resistance of theholes. With a centrifugal pressure of about 4,840 lbs. per inch, 1,960lbs. per square inch pressure is needed in the rotor reservoir. When oneutilizes a 1(l0)- inch diameter drop of liquid oxygen and methane at theambient pressure of a satellite environment of 2.53(10)- mm. Hg, thedroplet would evaporate very fast initially, since the mean latent heatof vaporation (81.2 calories per gram) is large compared tothe meansspecific heat (5383 calorie per gram per degree Centigrade) and the meanheat of fusion (5.2 calories per gram). With these conditions the dropquickly freezes and continues to evaporate until the vapor pressurefalls to the ambient pressure. Approximately 61 percent of the originaldrop mass is left at the equilibrium pressure Assuming a failure ofdetonation of some of the droplets, the velocity of the shock frontwould cause the droplet to pick up the velocity of the shock front inview of the relatively large ratio of area to mass of the droplet. Thisvelocity would be achieved in .012 inch; therefore, the pellets wouldevaporate a short distance back of the shock front where combustionwould add energy to the shock front in the same manner and eifect as ifit were detonated by the detonator.

From the foregoing, it can be seen that a novel warhead and method andapparatus for making the same has been presented which utilizes theprinciple of implosion whereby greater force upon a target is exertedthan occurs with the explosion phenomenon.

Although the invention has been described relative to particularembodiments, it should be understood that the invention is capable of avariety of alternative embodiments within the spirit and scope of theappended claims. For example, the mode of control of the explosion ofthe detonators could be a simple timing mechanism rather than theutilization of light operated detectors or computer controlled radiosignals.

What I claim is:

1. An imploding cloud warhead comprising an airborne unconfined shell ofexplosive particles, and a series of detonators peripherally locatedabout the outer extremity of said shell of explosive particles, saiddetonators being fuzed to fire in the optimum relative phases to producean implosion of said explosive particles to cause a high velocity shockwave to impact a target within the outer periphery of said shell.

2. The combination of claim lincluding a series of darts located at theinner periphery of said shell of explosive particles, said darts havinga parachute structure releasably secured to each dart such that thedetonation products behind said shock wave react with said parachutes toimpart a high velocity to said darts in the direction of travel of saidshock wave.

3. In combination, a cloud of outwardly moving explosive particles, anda series of outwardly moving detonators which maintain a peripheralposition around said cloud, said detonators being arranged to be firedat relative phases to produce an implosion of said explosive particlesto cause a high velocity shock wave to impact a target within saidcloud.

4. The combination defined in claim 3- including a series of darts, aparachute structure secured to each of said darts, said darts with saidparachute structures being outwardly moving and occupying a peripheralposition within said cloud such that the detonation products behind saidshock Wave imparts a high velocity to said darts in the direction oftravel of said shock wave toward a target.

5. The combination as defined in claim 4 including ejector means to formsaid outwardly moving cloud of explosive particles, said ejector meanscomprising an outer stator, a series of small openings through saidstator, a rotor mounted to revolve within said stator and having itsouter surface in contact with the inner surface of said stator, saidouter surface of said rotor having slots therein for containingexplosive material under pressure to be ejected, a reservoir connectedwith said slots such that explosive material under high pressure passesfrom said reservoir into said slots and when a slot passes over a set ofstator openings said explosive material is ejected from said openings toform said cloud.

6. The combination as defined in claim 5 including means for mixing twoliquids to form the material to be fed to said rotor, said mixercomprising a pair of cylinders each containing one of said liquids, apiston for each of said cylinders, a pressurized gas source for drivingsaid pistons from one end of said cylinders to the other, outlet meansin the other ends of said cylinders, conduit means connected to saidoutlets for premixing said fluids driven from said cylinders uponmovement of said pistons by said pressurized gas source, ultrasonicmixing means connected with said premixing chamber, conduit meansconnected with said ultrasonic mixing means and the first-mentioned endsof said cylinders to return fluid thereto, and means for driving saidpistons toward said first-mentioned ends of said cylinders, said conduitmeans serving as an outlet and connected with said reservoir.

7. The combination as defined in claim 6 including a check valveconnected in said conduit means to inhibit passage of said mixed fluidsinto said ultrasonic mixing means when said pistons are driven towardsaid firstmentioned ends of said cylinders.

8. An imploding cloud warhead comprising an air-borne unconfined shellof explosive particles, and a series of detonators peripherally locatedabout the outer extremity of said shell of explosive particles, saiddetonators being fuzed to fire in the optimum relative phases to producean implosion of said explosive particles to cause a high velocity shockwave to impact a target in the center of said shell.

9. The combination of claim 8 including a series of darts located at theinner periphery of said shell of explosive particles, said darts havinga parachute structure releasably secured to each dart such that thedetonation products behind said shock wave react with said parachutes toimpart a high velocity to said darts towards the center of said shell.

10. In combination, a cloud of outwardly moving explosive particles, anda series of outwardly moving detonators which maintain a peripheralposition around said cloud, said detonators being arranged to be firedat relative phases to produce an implosion of said explosive particlesto cause a high velocity shock wave to impact a target at the edge ofsaid cloud.

11. The combination as defined in claim 10 including a series of darts,-a parachute structure secured to each of said darts, said darts withsaid parachute structures being outwardly moving and occupying aperipheral position within said cloud such that the detonation productsbehind said shock wave imparts a high velocity to said darts in thedirection of travel of said shock wave toward a target.

12. The combination as defined in claim 11 including ejector means toform said outwardly moving cloud of explosive particles, said ejectormeans comprising an outer stator, a series of small openings throughsaid stator, a rotor mounted to revolve within said stator and havingits outer surface in contact with the inner surface of said stator, saidouter surface of said rotor having slots therein for containingexplosive material under pressure to be ejected, a reservoir connectedwith said slots such that explosive material under high pressure passesfrom said reservoir into said slots and when a slot passes over a set ofstator openings said explosive material is ejected from said openings toform said cloud.

13. The combination as defined in claim 12 including means for mixingtwo liquids to form the material to be fed to said rotor, said mixercomprising a pair of cylinders each containing one of said liquids, apiston for each of said cylinders, a pressurized gas source for drivingsaid pistons from one end of said cylinders to the other, outlet meansat both ends of said cylinders, conduit means connected to the outletsat said other ends of said cylinders for premixing said fluids drivenfrom said cylinder upon movement of said pistons by said pressurized gassource, ultrasonic mixing means connected with said premixing chamber,conduit means connected with said ultrasonic mixer and said outlets atsaid one ends of said cylinders to return fluid thereto, and means fordriving said pistons toward said one ends of said cylinders, saidoutlets at said one ends of said cylinders being connected with saidreservoir.

14. The combination as defined in claim 13 wherein said ultrasonicmixing means includes resonant wedges vibrated at a high frequency toachieve mixing.

15. A means for forming an imploding cloud warhead comprising a housing,ejector means on said housing for ejecting small particles of explosivesin a direction outwardly from said ejectors, means in said housing forrotating said ejectors such that said outwardly moving particles form agenerally spherical cloud, means mounted on said housing for firingdetonators toward the outer periphery of said cloud of explosivematerial to assume a peripheral position at the outer limits of saidcloud, means for projecting dart and parachute assemblies toward theouter periphery of said cloud to assume positions within the outerlimits of said cloud, and means for firing said detonators at theiroptimum phases to produce an implosion of said explosive particles tocause a high velocity shock Wave to travel toward a target within theouter periphery of said shell, said shock wave reacting with saidparachutes of said assemblies to cause said darts to travel toward'saidtarget.

16. A method for creating an imploding cloud warhead comprising thesteps of'radially emitting explosive particles to form a sphericalcloud, positioning detonators around the outer periphery of said cloudand positioning parachute and dart assemblies within the outer peripheryof said cloud.

17. The method as defined in claim 16 including the step of explodingsaid detonators at their optimum relative phases to produce an implosionof said explosive particles thereby causing a high velocity shock waveto travel toward a target within said shell while carrying saidparachute and detonator assemblies toward said target.

References Cited UNITED STATES PATENTS 211,778 1/1879 Pierce 102-482,372,264 3/1945 Firth 102-6 2,376,227 5/1945 Brown 1027.2 X 2,695,00211/1954 Miller 23938O X 2,703,527 3/1955 Hansen 1026 2,851,094 9/1958Griffin 891 2,925,038 2/1960 Walker 89-1 2,763,210 9/1956 Church et a1.10224 SAMUEL W. ENGLE, Primary Examiner US. Cl. X.R. l022, 9, 22, 56

1. AN IMPLODING CLOUD WARHEAD COMPRISING AN AIRBORNE UNCONFINED SHELL OFEXPLOSIVE PARTICLES, AND A SERIES OF DETONATORS PERIPHERALLY LOCATEDABOUT THE OUTER EXTREMITY OF SAID SHELL OF EXPLOSIVE PARTICLES, SAIDDETONATORS BEING FUZED TO FIRE IN THE OPTIMUM RELATIVE PHASES TO PRODUCEAN IMPLOSION OF SAID EXPLOSIVE PARTICLES TO CAUSE A HIGH VELOCITY SHOCKWAVE TO IMPART A TARGET WITHIN THE OUTER PERIPHERY OF SAID SHELL.